Removable blood clot filter with edge for cutting through the endothelium

Abstract

A removable blood clot filter includes anchor members with a sharp edge configured so that when the filter is removed the sharp edge aids in passing the anchor members through endothelial tissue. The filter may also include a sharp edge on locator members configured to aid pulling the locator members away from the endothelial tissue.

1. A removable filter to be placed in a flow of blood through a blood vessel having a wall, the filter comprising:
 a) a head having proximal and distal end portions and a central longitudinal axis; 
 b) a plurality of filter members extending from the head in generally one direction that is distally of the head, at least some of the filter members having a first larger diameter and a distal end, a tapered portion affixed to said distal end and a hook attached to said tapered portion opposite said distal end, each hook including a curved section extending distally away from said tapered portion and laterally away from said central longitudinal axis, said curved portion having a radius of curvature larger than said first diameter, said hook terminating at a hook free end that is spaced away from the distal end of the filter member with a gap in between said filter member distal end and said hook free end, said hook defining a plane; 
 c) wherein said hook is of a second smaller diameter when compared to the first larger diameter of said filter member; and 
 d) a sharp edge spanning at least a portion of at least one of the filter members and extending to said tapered portion, said sharp edge extending from said tapered portion toward said curved portion but terminating before extending over a majority of the curved portion of the hook so that the hook curved portion is able to straighten during removal from the wall of the blood vessel, said sharp edge being in said plane. 
 
     
     
       2. The filter according to  claim 1 , wherein the sharp edge extends over a portion of the at least one filter member adjacent to a wall of the blood vessel when the filter is positioned in the blood vessel. 
     
     
       3. The removable filter of  claim 1  wherein the sharp edge extends above and below the tapered section. 
     
     
       4. The filter according to  claim 1 , wherein the at least one filter member also includes a locator member. 
     
     
       5. The filter according to  claim 1 , wherein the hook further includes a second sharp edge over at least a portion of the filter member. 
     
     
       6. The filter according to  claim 5 , wherein the hook further includes a third sharp edge over at least a portion of the filter member. 
     
     
       7. The filter according to  claim 1 , wherein the sharp edge projects toward a longitudinal axis of the filter. 
     
     
       8. The filter according to  claim 1 , wherein the sharp edge is formed by removing a portion of the filter member. 
     
     
       9. A filter to be placed in a blood vessel having a wall, the filter comprising:
 a) a hub disposed along a longitudinal axis, the hub having proximal and distal end portions; 
 b) a plurality of legs branching away from the hub in generally one direction that is distally of the hub, each leg including a leg distal end portion of a first, larger diameter and a tapered portion; 
 c) a hook that (i) is configured to penetrate a wall of the blood vessel, (ii) is spaced along the longitudinal axis from the hub, and (iii) has a curved portion that curves radially away from the longitudinal axis; 
 d) wherein said hook extends distally of said tapered portion, said hook defining a plane and having a free end spaced radially away from the leg distal end and radially away from said longitudinal axis a first radial distance, there being a gap in between said hook free end and said leg distal end that is larger than said first larger diameter; 
 e) a blade extending above and below the tapered portion over both a portion of the leg distal end portion and over at least part of the hook; 
 f) wherein the hook curved portion has a reduced diameter distally of said leg distal end portion so that said hook curved portion is able to straighten during removal from the blood vessel wall; 
 g) a plurality of locator members branching from the hub; and 
 h) wherein said blade occupies said plane. 
 
     
     
       10. The filter according to  claim 9 , wherein each locator member includes:
 a base portion proximate the hub; 
 a first portion that extends from the base portion and along a first axis; 
 a second portion that extends from the first portion and along a second axis, which is distinct from the first axis; and 
 a tip portion that extends from the second portion and along a tip axis, which is distinct from the first and second axes, the tip portion (i) is configured to engage the wall of the blood vessel, (ii) is spaced along the longitudinal axis from the hub, and (iii) is radially spaced from the longitudinal axis a second distance, which is less than the first radial distance. 
 
     
     
       11. The filter according to  claim 10 , wherein each locator member further includes on the tip portion a sharp edge projecting toward the longitudinal axis. 
     
     
       12. A filter to be placed in a blood vessel, the filter comprising:
 a) a hub disposed along a longitudinal axis, the hub having proximal and distal end portions; 
 b) a plurality of legs branching away from the hub, each leg including a leg proximal end attached to the hub and a leg distal end having a first diameter and a tapered portion; 
 c) a hook that (i) is configured to penetrate a wall of the blood vessel, (ii) is spaced along the longitudinal axis from the hub, and (iii) has a hook curved portion that curves radially away from the longitudinal axis a first distance; 
 d) wherein said hook curved portion extends distally of said tapered portion, said hook curved portion defining a plane and having a first hook end attached to tapered portion and a second hook end that is a free end spaced radially away from the leg distal end and radially away from said longitudinal axis, there being a gap in between said hook free end and said leg distal end that is larger than said first diameter; 
 e) a blade extending over both the tapered portion of the leg and over a portion of the hook, wherein the blade does not extend over a majority of the hook so that the hook curved portion that extends distally of the blade is able to straighten during removal from the blood vessel wall; and 
 f) a plurality of locator members branching from the hub. 
 
     
     
       13. A removable filter to be placed in a flow of blood through a blood vessel, the filter comprising:
 a) a head having proximal and distal end portions and a central longitudinal axis; 
 b) a plurality of filter members extending distally of the head, at least some of the filter members having a first diameter and a distal end; 
 c) a tapered portion affixed to said filter member distal end; 
 d) a hook shaped anchor attached to said tapered portion opposite said filter member distal end; 
 e) each hook shaped anchor including a hook curved portion extending distally away from said tapered portion and laterally away from said central longitudinal axis, said hook curved portion having a radius of curvature, said hook shaped anchor terminating at a hook free end that is spaced away from the distal end of the filter member with a gap in between said filter member distal end and said hook free end, said hook curved portion defining a plane; 
 f) wherein said hook curved portion is of a reduced diameter when compared to the diameter of said filter member; 
 g) a blade spanning over at least a portion of at least one of the filter members and above and below the filter member distal end; and 
 h) said blade not extending from said tapered portion along the entire hook curved portion so that the hook curved portion that extends distally of the blade is not reinforced by the blade and is able to straighten during removal from the blood vessel wall.